The four weapons that authorities say were used in the massacre at a Colorado theater showing of the latest Batman movie included a popular semiautomatic rifle, a .223-caliber assault-style rifle with a 100-round drum magazine.

The suspect also had two .40-caliber Glock handguns and a 12-gauge Remington Model 870 pump shotgun.

In the past 60 days, police said, Holmes bought more than 6,000 rounds of ammunition, at gun shops and over the Internet, including:

3,000 rounds of .223-caliber ammunition for the rifle. It was described as an AR-15-type weapon built by Smith and Wesson.

3,000 rounds of .40-caliber ammunition for the Glock handguns.

300 rounds for the shotgun.

AR-15 is a Colt trademark, but similar weapons are built by other manufacturers. It typically fires a .223-caliber round and can accommodate large ammunition clips. The rifle is the semiautomatic civilian version of the U.S. military’s M-16, which first came into wide use during the Vietnam War.

Aurora Police Chief Dan Oates said a 100-round drum magazine was recovered at the shooting scene. He said that it could have been used to fire up to 60 shots in a minute. On Friday, 12 people were killed, and another 58 injured, all but a few by gunfire, he said.

Officials told NBC News that all four were purchased legally, beginning in May, from two national chain stores: Gander Mountain Guns and Bass Pro Shops.

Bass Pro Shops released a statement saying that employees at a Denver store followed all laws when they sold two weapons to Holmes. "We want to offer our deepest sympathies to the victims and their families," said Larry Whiteley, manager of communications for the company. "This is an unspeakable tragedy, and we join with all Americans in offering our prayerful support. Based on the records we have reviewed, personnel in our Denver store correctly and fully followed all Federal requirements with respect to the sale of one shotgun and one handgun to the individual identified in this incident. Background checks, as required by Federal law, were properly conducted, and he was approved. Again, our hearts go out to the victims and their families. We also offer our support and appreciation to the law enforcement and emergency response professionals and all others who responded to give aid to these innocent victims."

Several politicians and a coalition of gun-control groups called for new restraints on guns.

A statement by the coalition read in part: "Gun violence is preventable. It is long past time for policymakers at all levels to act. Americans have a right to feel safe in their communities--in schools, restaurants, movie theaters, and all public places. Using the cynical desires of the gun lobby and firearms industry as an excuse for inaction is shameful."

Suspect James Eagan Holmes reportedly never said a word while allegedly shooting 71 people and killing 12 in a sold-out showing for Batman movie "The Dark Knight Rises." Colorado Governor John Hickenlooper said it was "the act of a very deranged mind." NBC's Miguel Almaguer reports.

Sen. Frank Lautenberg, D-N.J., issued a statement saying: “Our hearts are filled with sadness for the 12 people killed and the dozens wounded in this senseless act. We have to face the reality that these types of tragedies will continue to occur unless we do something about our nation's lax gun laws."

According to the Brady Campaign/Brady Center to Prevent Gun Violence, Colorado ranks among states with weaker gun laws. On Brady’s 100-point scorecard, Colorado scored 15. The states with the lowest ranking, 0, were Alaska, Arizona and Utah. California had the highest score, 81. According to the Brady Center, the score is based on laws that can prevent gun violence, such as background checks on all guns sales, permit-to-purchase requirements, limiting handgun purchases to one a month, and retention of sales records.

A spokesman for the National Rifle Association issued a short statement on the incident.

“Our thoughts and prayers are with the victims, their families and the community. NRA will not have any further comment until all the facts are known,” said Andrew Arulanandam, NRA director of public affairs.